1. Field of the Invention
The invention relates to fire-resistant materials, and in particular, to a multilayer fire-resistant material.
2. Description of the Related Art
Fire resistant or fire retardant materials can be used as architectural or decorative materials. Architectural materials disclosed in Taiwan Patent Nos. 583,078 and 397,885 primarily comprise a stacked layer, serving as a fire resistant layer, made of nonflammable inorganic materials such as pearlite (or perlite), MgCl2, MgO, CaCO3 or cement. In addition, a stiff fire resistant laminate can be obtained from flexible substrates made of fibers or non-wovens blended with flame retardants, foaming agents and 50˜80% inorganic materials by weight.
Fire resistant coatings, serving as decorative materials, disclosed in Taiwan Patent Nos. 442,549, 499,469 and 419,514 comprise a combination of foaming and intumescent agents, carbonization agents, flame retardants, and adhesives which foam and intumesce under fire exposure. U.S. Pat. No. 5,723,515 discloses a fire-retardant coating material including a fluid intumescent base material having a foaming agent, a blowing agent, a charring agent, a binding agent, a solvent, and a pigment, for increasing resistance to cracking and shrinking. A compound disclosed by U.S. Pat. No. 5,218,027 is manufactured from a composition of a copolymer or terpolymer, a low modulus polymer, and a synthetic hydrocarbon elastomer. The fire retardant additive comprises a group I, group II or group III metal hydroxide with the proviso where at least 1% by weight of the composition is in the form of an organopolysiloxane. U.S. Pat. No. 6,262,161 relates to filled interpolymer compositions of ethylene and/or alpha-olefin/vinyl or vinylidene monomers, showing improved performance under exposure to flame or ignition sources, and fabricated articles thereof. The articles are often in the form of a film, sheet, a multilayered structure, a floor, wall, or ceiling covering, foams, fibers, electrical devices, or wire and cable assemblies. Conventional flame retardant polymer compositions are obtained by physically blending organic polymer and inorganic flame retardant, wherein coupling agents or surfactants are typically incorporated to improve the dispersity of the inorganic flame retardant. However, because the organic polymer does not react with inorganic component to form a well-structured composite by the formation of chemical bonds, conventional flame retardant compositions easily melts, ignites, or produces flaming drops under exposure to flame or ignition sources.
Specifically, the heated area of the conventional fire resistant material can be carbonized rapidly and expand 8˜10 times in volume over the original material size due to foaming, intumescent, and carbonization agents contained therein. However, after long term heating, the intumescent carbonization layer (or the heated part) cracks slightly and peels, such that flame and heat can directly transfer to the interior materials. Accordingly, an improved fire resistant material is desirable.
A fire-resistant organic/inorganic composite is disclosed in detail in commonly assigned U.S. patent application Ser. No. 11/410,913, filed on Apr. 26, 2006, the teachings of which are hereby incorporated by reference. In the organic/inorganic composite, inorganic particles are well dispersed in and reacted with an organic matrix. The inorganic particles strengthen the mechanical properties of the structure through the reaction between inorganic and organic materials, so that a char layer formed on the surface can maintain its structural integrity without peeling or cracking, effectively preventing direct heat transfer to the interior. As a result, the duration of fire resistant ability is tremendously improved.